The reaction between solid sodium and iron(III) oxide is one in a series of reactions that inflates an automobile airbag.

6 Na(s) + Fe2O3(s) 3 Na2O(s) + 2 Fe(s)

If 171.0 g Na and 213.5 g Fe2O3 are used in this reaction, what is the mass of excess reactant that remains after the reaction is complete?